This invention relates generally to removable guard members for power tools, and, in particular, to a removable guard member for hand-held power tools such as an angle grinder wherein the inner circumferential portion of the clamp ring of the guard has at least a partially-knurled surface.
Conventional power tools use a guard to protect users and others in the area from debris, or possibly grinding wheel fragments. Such guards are especially useful in hand-held grinding/sanding power tools such as angle grinders having spindles on which work wheels, e.g., grinding wheels, sanding wheels, and the like, are mounted.
In a typical guard, one used on an angle grinder for example, the guard is mounted onto the lower bearing housing of the angle grinder.
The guard typically includes a clamp ring and a guard hood. The clamp ring mounts onto a flange of the lower bearing housing.
The clamp ring is typically a stamped metal ring. In the past, the inner circumferential portion of the clamp ring has generally been of a smooth texture. The flange of the lower bearing housing has generally been a machined aluminum part. While this guard, used in combination with the machined-aluminum lower bearing housing, has been sufficient to pass UL/ANSI-standard guard testing procedures, the machined-aluminum lower bearing housing is expensive to manufacture.
In accordance with the present invention, the above and other problems are solved by providing a removable guard for a power tool able to utilize, and preferably used in conjunction with, a semi-elastic lower bearing housing. The guard, typically for a hand-held angle grinder, includes a clamp ring which has at least a partially-knurled surface located on its inner annular circumferential portion.
In the present invention, a removable guard is configured to cover an area proximate a spindle assembly of the tool, such as an angle grinder, between the spindle assembly and a user of the tool. The guard is configured to be securely mounted to a lower bearing housing, supporting the spindle assembly of the tool, and being formed of a semi-elastic material such as a molded polymer-based lower bearing housing, or any suitable semi-elastic component made of including, but not limited to, non-polymeric materials, non-polymeric composites, polymer composites, and polymer materials containing filling agents or plasticizers. The guard, when mounted to the lower bearing housing, and when in use during operation of the tool, is designed to remain functional even under conditions of flying debris, or grinding wheel fragments, such as under conditions of an exploding, rotating abrasive wheel mounted on the semi-elastic lower bearing housing of the tool.
The guard includes a guard hood configured to cover the area proximate the spindle assembly, between the spindle assembly and the user of the tool. A clamp ring depends from, and is mechanically coupled, to the guard hood.
The clamp ring has an inner circumferential portion and is configured so that the inner circumferential portion at least partially surrounds, and can be securely tightened around, at least a portion of the semi-elastic lower bearing housing. The clamp ring is configured so that at least a portion of the semi-elastic lower bearing housing can pass essentially concentrically through the clamp ring.
The inner circumferential portion of the clamp ring defines at least a partially-knurled surface. When the clamp ring is securely tightened around the semi-elastic lower bearing housing, the at least partially-knurled surface of the clamp ring inner circumferential portion compresses into the semi-elastic lower bearing housing to securely mount the guard member to the machine tool.
The power tool, typically an angle grinder, to which the guard attaches has a motor housing and a gear housing portion. The gear housing is adjacent the lower bearing housing. The lower bearing housing supports the spindle assembly, and the spindle extends outwardly from the lower bearing housing. The spindle of the spindle assembly includes a tool attachment portion. The lower bearing housing includes a flange to which the guard is secured.